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Dr. D. Love
Dr. D. Love, Doctor
Category: Medical
Satisfied Customers: 18780
Experience:  Family Physician for 10 years; Hospital Medical Director for 10 years.
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I keep testing positive for cocain and terbinafine hcl 250

Customer Question

I keep testing positive for cocain and terbinafine hcl 250 mg is the only medication i am currently taking. I never tested positive before i started taking this medication
JA: OK. The Doctor will need to help you with this. Please give me a bit more information, so the Doctor can help you best.
Customer: I just wanted to know if terbinafine could be the cause of failing the urine screen. Im confused i never failed a test before i started taking terbinafine
JA: Is there anything else important you think the Doctor should know?
Customer: No that's all
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Submitted: 1 year ago.
Category: Medical
Expert:  Dr. D. Love replied 1 year ago.

Hello from JustAnswer.

There is no clinical evidence that terbinafine will cause a false positive for cocaine on urine drug screening tests. However, if you only started having positive results on screening tests after taking the terbinafine, that would be suspicious that it would be the cause of false positive results in you.

The usual next step would be to perform a confirmatory test, such as gas chromatography/mass spectrometry, or GC/MS. If the GC/MS test is negative for cocaine, that would prove that the screening test is a false positive. The GC/MS does not prove what is causing a false positive, only that it is a false positive. Since false positive results occur on a regular basis, even in someone that is not taking any medicines, the only way to prove that terbinafine is causing the false positive would be to show that the rate of false positives in higher in people taking terbinafine compared to people that are not taking terbinafine.

If I can provide any additional information, please let me know.

Expert:  Dr. D. Love replied 1 year ago.

Please let me know if I can provide any further assistance.

If you would like my assistance with any future questions, I can be reached through my profile at